1. Universidade Católica Portuguesa, Católica Lisbon School of Business and Economics, 1649-023 Lisbon, Portugal;
2. Vlerick Business School, Technology and Operations Management Area, 3000 Leuven, Belgium;
3. Katholieke Universiteit Leuven, Research Center for Operations Management, 3000 Leuven, Belgium;
4. Kellogg School of Management, Northwestern University, Evanston, Illinois 60208;
5. Olin Business School, Washington University in St. Louis, St. Louis, Missouri 63130